Cellulosic structures and methods for producing same



Patented Feb. 9, 1937 PATENT OFFICE CELLULOSIC STRUCTURES AND METHODSFOR. PRODUCING SAME Winfield Walter Heckert, Ardentown, DeL, as-

signor, by mesne assignments, to E. I. du Pont de Nemours & Company,Wilmington, Del., a corporation of Delaware No Drawing. ApplicationSeptember 15, 1934,

8 Claims.

This invention relates to cellulosic structures such as filaments,threads, fabrics, sheets, films, claps, tubing, or the like. Moreparticularly, this invention relates to cellulosic structures of thetype just mentioned having a subdued or low luster or that are more orless opaque.

In the ordinary methods of preparing cellulosic structures, such asfilaments, threads, films, caps, tubing, etc., from-viscose,cuprammonium, nitrocellulose, cellulose acetate and other cellulosicsolutions (without the addition of opaquing or low luster-inducingagents to the solutions) ,the products are transparent or translucent orvery highly lustrous. For many purposes, transparency, brilliant sheenand luster are not desirable and thus restrict the uses of thematerials. Recently, various methods have been proposed for producingcellulosic structures having a low or subdued luster or opacity.

I have found that I, can produce cellulosic structures characterized bya low luster or opacity by incorporating therein a tertiary amine of thecharacter described in detail hereinafter which imparts opacity or lowluster by remaining in the cellulosic structure.

An object of the invention comprises the production of new opacified orlow luster cellulosic structures. A further object of the inventionrelates to the production of novel cellulosic structures containingorganic compounds which remain in the finished article and which impartopacity or low luster. Other objects of the invention will appearhereinafter.

The objects of the invention are accomplished in general byincorporating in the cellulosic solution from which the structure is tobe produced an opaquing or a low luster-inducing agent of the typehereinafter more fully explained.

The low luster-inducing agent contemplated by this invention is anorganic compound of high molecular weight having a tertiary aminegrouping and comprising two or more carbocyclic or heterocyclic nucelihighly deficient in hydrogen.

So far as the instant invention is concerned, each closed chain ofcarbon or heteroatoms or combination of carbon and heteroatoms will beconsidered a nucleus. Thus, benzene, naphthalene and carbazole have one,two, and three nuclei respectively.

These opaquing or low luster-inducing agents, which are preferably whitein color, possess a sufiiciently low vapor pressure and are suflicientlyinert to resist the change or removal from the cellulosic structure inthe ordinary process of Serial No. 744,258

making and finishing the same during the manufacture thereof. They alsoeffectively resist removal or change during any of the usual processesto which the finished cellulosic structure may be subjected, such asboiling-off, dyeing, bleaching, washing, ironing, etc. These substancesare incompatible with the mass of the substance constituting the finalproduct. They may be soluble but, in the preferred embodiment of thisinvention, they are insoluble in the solution from which the structureis prepared.

Highly effective delusterants function in particular by reason of theiropacifying power which is a function of the difference in refractiveindex between the delusterant particle and the surrounding medium. Thosein my preferred range differ from the index of the medium by at least0.10 and the greater this diiference, the more effective the compound asan opacifier or delusterant. Most organic compounds have several indexesand the statement just made refers to the highest index of the compoundor to any one of the several indexes.

As illustrative examples of tertiary amines coming within the scope ofthis invention are the following:

Dibenzyl aniline Ethyl benzyl aniline Triphenyl amine Ethyldiphenylamine Methyl diphenylamine Dimethyl anthranylaminePhenyl-di-s-naphthyl amine Dimethyl-u-naphthylamineDimethyl-p-naphthylamine Di-ethyl-a-naphthylamineDi-ethyl-p-naphthylamine 1 Ethyl-di-p-naphthyl amineBenzyl-di-a-naphthyl amine Diphenyl-u-naphthyl amine Phenyl-di-biphenylamine Tetra-phenyl-ethylene diamine Tetra-phenyl-phenylene diamineDiphenyl benzthiazyl amine Phenyl difurfuryl amine Di-ethyl-a-naphthylamine Methenyl diphenyl amine The scope of this invention is notintended to include compounds the only tertiary nitrogen of which is anamide nitrogen. In other, words, the invention contemplates only trueamines and not amides.

The organic compounds contemplated as delusterants in accordance withthe principles of this invention are embraced in the following formula:

1?: Rl N', R3

in which at least two carbocyclic or heterocyclic nuclei highlydeficient in hydrogen are included, and in which R1, R2 and R3 areradicals other than hydrogen. One of the radicals may be naphthyl, forexample, in which event the other radicals need not contain a cyclicnucleus, or, alternatively, two or more of the radicals may contain aphenyl group or a substituted phenyl group. The cyclic nuclei may beattached directly to the nitrogen atom, for example, as intriphenylamine, or some of them may be indirectly attached through thelinkage of an alkyl group as in the case of benzyl-di-naphthyl amine.Where the other conditions are fulfilled, the invention contemplates anN attached radical which may be aliphatic (either saturated orunsaturated, e. g. alkyl or alkylene), an aromatic, aralkyl or alkaryl,alicyclic or heterocyclic. By way of illustrating specifically thoseradicals which may be attached to the N atom of the tertiary amine, thefollowing groups may be mentioned: e. g. methyl, phenyl, benzyl, or aheterocyclic group linked thru carbon or their colorless substitutionproducts, such as their -R, -O--R, S-R, Se--R, TeR, -NHR, COR, -SO2-R,SO-R, hydroxy alkyl and halogen derivatives where R. may be an alkyl,

'aryl, aralkyl, alkaryl, or a heterocyclic group.

Organic compounds of the character described which have relatively highrefractive indexes and. which are preferred on the basis of cost, colorstability, acid insolubility and effectiveness are the following:

Triphenyl amine Methenyl-diphenyl-diamine Phenyl-di-beta-naphthylamineEthyl-di-alpha-naph'thyl amine Benzyl-di-alpha-naphthyl amineTetra-phenyl-phenylene diamine Tetra-phenyl-ethylene diamineDiphenyl-a-naphthyl amine The quantity of the low luster-inducing oropaquing agent which may be,used may vary within wide limits, dependingprincipally upon the opaquing and luster desired in the final product.Cellulosic structures containing these low luster-inducing or opaquingagents in amounts ranging from 0.10-20.0% by weight have givensatisfactory results, but, of course, it is obvious that smaller orlarger quantities may be employed as desired. When a viscose solution isemployed, satisfactory results may be secured if it contains 7%cellulose and from 0.01-1.5% more or less of the low luster-inducing oropaquing agent.

If desired, the low luster-inducing agents contemplated by the instantinvention may be used in combination with each other or with other lowluster-inducing agents, such as-mineral oil, petroleum jelly, waxes,paraffin, benzene, toluene, pine oil or inorganic pigments, such astitanium oxide, lithopone, zinc sulfide, etc.

The low luster-inducing agent may be added to the solution at any stagein the course of the manufacture thereof, or after the preparation ofthe solution and prior to the spinning, extrusion or casting operation.It may be added directly, if the particle size is satisfactory, or aftersuitable adjustment of the particle size by any of the well knownmethods, such as emulsification, grinding in a colloid mill or pebblemill, or in the form of a suspension or emulsion prepared with orwithout the assistance of suitable dispersing agents or protectivecolloids, such as soaps, sulfonated oils, alkyl naphthalene sulfonates,sodium caseinate, etc. or combinations thereof.

In order to more fully explain the principles of this invention, thefollowing illustrative examples are given: 7

Example I.One hundred parts of molten dibenzyl aniline are emulsifiedwith 400 parts of water containing 8 parts casein, 2.4 parts of hydratedsodium phosphate and 2 parts of Monopole oil by passing the mixturethrough a colloid mill such as a Disper-mill at a temperature of C; Theresulting emulsion, consisting of droplets 1-4 microns in diameter, iscooled and incorporated in viscose containing 7% cellulose and 6%causticsoda in the proportion of 1 to 20. This dispersion is ripened tothe desired index and spun into rayon 'or cast into sheets. Theresulting product has a desirable low luster.

Example II.-'Four hundred parts of ethyl dibeta-naphthylamine' (Berichte20, 2619) are ground with 8 parts of sodium caseinate and 592 parts ofwater in a ball mill until practically all the particles lie below 4microns in diameter. One per cent of this dispersion is incorporated inviscose and, after ripening, the latter is spun into rayon. The producthas a beautiful low luster similar to that obtained with inorganic Ipigments.

It is to be understood that these examples do not in any way restrictthe invention thereto but merely illustrate several specific andpreferred embodiments which have given satisfactory results.

Though the preferred embodiments of this invention contemplate theincorporation of the low luster-inducing agent in the solution at sometime prior to the extrusion or casting thereof, satisfactory results maybe secured also by applying the low luster-inducing agent to apreviously formed cellulosic structure. In other words, the lowluster-inducing agent may be incorporated in the final cellulosicstructure by an after-treatment.

Though the invention has been specifically described in connection withthe viscose process, it is obvious that the principles thereof areequally applicable to the cuprammonium cellulose, cellulose nitrate, andcellulose acetate processes.

In the case of cellulosic solutions of wholly organic solvents, it isonly necessary that a suitable choice of amine be made so that thesolu-.

bility characteristics do not interfere. It has 4 already been pointedout that the low lusterinducing substance must be incompatible with themass of substance constituting the final product. In addition, in thecase of cellulose acetate or nitrate spinning solutions, it ispreferable that the low luster-inducing substances be insoluble hi thesolvent employed. However, resinous materials and certain crystallized.substances soluble in the solvent, precipitate, on the evaporation ofthe solvent, in the cellulose acetate in the form of fine amorphous orcrystalline particles 'sufiiciently small and well distributed to avoidharmful effect on the physical properties of theresulting structure. Theadvantage in such cases lies in avoiding the necessity for emulsifyingor grinding the compounds to obtain suitable subdivision. Suitablecompounds may be readily 7 I 2,069,805 selectedfrom any specific-systemby one skilled in the art.

While the invention has been described generally with respect to the useof the various compounds mentioned herein in opaquing cellulosicstructures prepared by casting or spinning methods, it is desired toemphasize the fact that these compounds are of special benefit in thespinning of artificial silk. Thus, undelustered artificial silk has ashade and luster which isundesired fora great many purposes. Inaccordance, with the present invention, it is possible to produceartificial silk, particularly of the regenerated cellulose type preparedfrom viscose or cuprammonium cellulose, having a pleasing dullappearance, the dullness being of any degree desired, in which theopaquing or delustering agent is uniformly distributed and which doesnot interfere with the tenacity of the yarn to any large extent.

Since it is obvious that various changes and modifications may be madein the above description without departing from the nature or spiritthereof, this invention is not restricted thereto except as set forth inthe claims.

I claim:

1. Delustered cellulosic articles prepared from cellulosic solutionscontaining, in a phase distinct from that of the cellulosic materialtherein a finely divided, white delustering agent comprising apolycyclic tertiary amine, said amine having a refractive index whichdiffers from the refractive index of the surrounding medium by at least0.1.

2. Delustered cellulosic articles prepared from cellulosic solutionscontaining, in a phase distinct from that of the cellulosic materialtherein, a finely divided, white delustering agent comprising a tertiaryamine having at least two cyclic nuclei, at least one of said nucleibeing directly attached to the nitrogen atom of the amine, said aminehaving a refractive index which differs from the refractive index of thesurrounding medium by at least 0.1.

3. Delustered cellulosic articles prepared from cellulosic solutionscontaining, in a phase distinct from that of the cellulosic materialtherein, a finely divided, white delustering agent comprising a tertiaryamine having at least two cyclic nuclei directly attached to thenitrogen atom of the amine, said amine having a refractive index whichdiffers from the refractive index of the surrounding medium by at least0.1.

4. Delusteredcellulosic articles prepared from cellulosic solutionscontaining, in a phase distinct from that of the. cellulosic materialtherein, a finely divided, white delustering agent comprising I atertiary amine taken from the class consisting of dibenzyl aniline,ethyl benzyl aniline, triphenyl amine, ethyl diphenylamine, methyldiphenylamine, dimethyl anthranylamine, phenyl-di-p-naphthyl amine,dimethyl-a-naphthylamine, dimethylfl-naphthylamine,di-ethyl-a-naphthylamine, diethyl p3 naphthylamine, ethyl-di p/ naphthylamine, benzyl di-a-naphthyl amine, diphenyl-anaphthyl amine,phenyl-di-bi-pheriyl amine, tetra-phenyl-ethylene diamine,tetra-phenylphenylene diamine, diphenyl benzthiazyl amine, phenyldifurfuryl amine, di-ethylm-naphthyl amine, methenyl diphenyl diamine.

5. Delustered regenerated cellulose articles containing,.in a phasedistinct from that of the regenerated cellulose, a finely divided, whitedelustering agent comprising 'a polycyclic tertiary amine, said aminehaving a refractive index which diifers from the refractive index of thesurrounding medium by at least 0.1.

6. Delustered regenerated cellulose articles containing, in a phasedistinct from that of the regenerated cellulose, 21. finely divided,white delustering agent comprising atertiary amine having at least twocyclic nuclei, at least one of said nuclei being directly attached tothe nitrogen atom of the amine, said amine having a refractive indexwhich differs from the refractive index of the surrounding medium by atleast 0.1.

'7. Delustered regenerated cellulose articles containing, in aphase-distinct from that of the regenerated cellulose, a finely divided,white de lustering agent comprising a tertiary amine having at least twocyclic nuclei directly attached to the nitrogen atom of the amine, saidamine having a refractive index which diifersfrom the refractive indexof the surrounding medium by at least 0.1.

8. Delustered regenerated cellulose articles containing, in a phasedistinct,from that of 'the regenerated cellulose, a finely divided,white delustering agent comprising a tertiary amine taken from the classconsisting of dibenzyl aniline, ethyl benzyl aniline, triphenyl amine,ethyl diphenylamine, methyl diphenylamine, dimethyl anthranylamine,phenyl-di-p-naphthyl amine, dimethyl-u-naphthylamine, dimethyl ,6naphthylamine, di-ethyl-a-naphthylamine, di-ethylp-naphthylamine,ethyl-di-p-naphthyl amine, benzyl di-a-naphthyl amine,diphenyl-anaphthyl amine, phenyl-di-bi-phenyl amine,tetraphenyl-ethylene diamine, tetra-phenyl-phenylene diamine, diphenylbenzthiazyl amine, phenyl difurfuryl amine, di-ethyl-a-naphthyl amine,methenyl diphenyl diamine.

WINFIELD WALTER HECKERT.

